1. Field of the Invention
This invention relates to aircraft loading bridges, commonly called airbridges, which provide a covered passageway for facilitating the transfer of passengers between an aircraft standing in a parked position at an airport and an airport terminal building, such airbridges consisting of a number of telescoping sections which are parked in a retracted state but which can be extended to reach and dock with an aircraft when the aircraft is appropriately parked for loading and unloading, the airbridge terminating in a cabin assembly having a door engageable with a door opening of the aircraft, to provide an access between the bridge and the aircraft.
2. Description of Related Art
It will be appreciated that an airbridge has to be capable of co-operating with different aircraft types in which the aircraft doors are at varying heights from the ground, as well as being extendable to engage the aircraft and being angularly movable to a limited extent, and for this purpose the airbridges are usually mounted on wheeled support structures incorporating elevating means for raising and lowering the airbridge.
Usually in such support structures the elevating means comprises a pair of elevating legs supporting the end section of the telescopic passageway, and positioned approximately midway along the section. Such an arrangement suffers from the disadvantage that as the structure is spaced some distance from the cabin assembly, any movement of the elevating legs becomes multiplied at the cabin end which complicates the control system, especially as the amount of correction that needs to be applied depends upon the length to which the airbridge has been extended in each particular case.
In addition, as the elevating legs are adjusted to raise or lower the airbridge, the resultant angular variation of the airbridge with respect to the ground will cause the legs to be tilted to a lesser or greater extent from the vertical, which imposes undesirable stresses on them.